[QE-users] It is neccesary to make a vc-relax in each DFT U+V calculation?

[ROBERT MIKHAIL GUZMAN ARELLANO]

Dear members,

I am starting to work in DFT U+V making calculations with pw.x and hp.x of
Quantum Espresso package. So my question is:

In order to calculate the U and V values with hp.x. What is the path to
follow?

At his time. I am doing these steps.

0. Calibrate pseudo potentials, k-points, and frequency of waves and
density.

1. Calculate the crystalline structure using vc-relax.

2. Make a scf calculation using the best atomic positions and unit
cell parameters obtained in vc-relax calculation. In this calculation, I
put a small value of U and V between orbitals. (1.d-3 eV)

3 run hp.x in order to calculate better values of U and V.

4 extract the U and V values calculated by hp.x, and put these in a new scf
calculation and run the last.

5 repeat the 3 step and after the 4 step until the U and V values between 2
different calculations look equal or with small difference (0.01eV).

My Question is: is it necessary to make a vc-relax between the 3 and 4
steps? I looked at some examples which do that  in order to calculate U
value,but do not do the same when calculating V (interaction between
different orbitals).

During this month I have been working with atoms whose valence orbitals are
S and P, and I understand that for these orbitals, not being very localized
like the D orbitals, it is necessary to work with U and V, where V responds
to the coulomb interaction between orbitals of neighboring atoms.

Thank's for your attention.

Best regards.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20240926/48a90863/attachment.html>